Fire Science Workbook 1

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NSW Rural Fire Service FireScience 1

INTRODUCTION

Every single person in our community is connected in one way or another with fire. Fire may

be disastrous in that it destroys our belongings and interrupts our way of life or fires may be

beneficial by providing us with an energy source which we can use to prepare meals, keep us

warm, transport us and our goods and maintain our standard of living. Developing a better

understanding of the nature and behaviour of

fire will enable us to maximise the benefits

and minimise the disastrous affects of fire.

It is within this context that FireScience

provides learning experiences through

which students can acquire scientific

knowledge, skills and attitudes within a

conceptual framework to facilitate the application

of their understanding to everyday life.

FireScience aims towards developing a fire sensible population that will be well informed

about fire behaviour, management and safety. This student based activity book relates

many of the scientific concepts of fire behaviour and management to the Syllabus Core

Content Areas of the NSW Science Syllabus in order to promote fire consciousness into the

teaching of science. Science provides a medium in which many of the fire safety concepts

introduced in primary school can be continued into the later years at school.

Teachers - Please note:

The activities in this workbook can be photocopied without permission provided that the

NSW Rural Fire Service is acknowledged as the source of resources.


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2 FireScience NSW Rural Fire Service

CONTENTS

WORKBOOK 1

1. AIR & GASES

Percentage of gases in the air ........................................................................................... 6

How much of the air is oxygen ........................................................................................... 7

Carbon dioxide and fire ...................................................................................................... 9

Recognising fire extinguishers ......................................................................................... 10

Oxygen and burning ......................................................................................................... 12

Hydrogen and oxygen ...................................................................................................... 14

Air pressure and sucking up liquids ................................................................................. 17

Air has weight and can exert pressure ............................................................................. 18

2. MATTER

Carbon dioxide gas in extinguishers ................................................................................ 21

Pressure and boiling ........................................................................................................ 22

Evaporation and sweating ................................................................................................ 23

Water in living things ........................................................................................................ 25

Gases, temperature and pressure ................................................................................... 29

Water tension ................................................................................................................... 30

Forming compounds ........................................................................................................ 32

Decomposition of compounds (sugar) ............................................................................. 34

3. MATERIAL SCIENCE

What cars are made of ..................................................................................................... 37

Flame testing of metals .................................................................................................... 39

Corrosion .......................................................................................................................... 41

Displacement of metals .................................................................................................... 43

House design and modification in bush fire prone areas ................................................. 45

Which building materials are the best to use in buildings in

bush fire prone areas. ...................................................................................................... 47

Making concrete ............................................................................................................... 49

Plastics ............................................................................................................................. 51

Recognising plastics ........................................................................................................ 53

Carbon compounds .......................................................................................................... 56

Flammability of alkanes.................................................................................................... 58

Using flammable liquids safely ......................................................................................... 59

Acetylene ......................................................................................................................... 60

What clothes burn ............................................................................................................. 62

Comparing the flammability of different types of fabric .................................................... 63


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4. ACIDS AND BASES

Listing acids in common usage ........................................................................................ 65

Making a model fire extinguisher ..................................................................................... 67

Typical properties of acids................................................................................................ 69

Battery acid ...................................................................................................................... 69

Car parts burning to produce acids .................................................................................. 71

Fire fighting foam ............................................................................................................. 73

5. FIRE AND THE HUMAN BODY

Body temperature............................................................................................................. 75

Heat stress, heat exhaustion and heat stroke .................................................................. 77

Circulation of blood .......................................................................................................... 80

6. WEATHERING AND EROSION

Heat and rocks ................................................................................................................. 82

Bush fires and soil erosion ............................................................................................... 84

WORKBOOK 2

7. MOTIONInertia

Stopping distances

Speed

Effect of wind on fire behaviour

Running away from a fire

Speed of water coming out of a hose

Friction

Tread patterns on tyres

Friction in hoses

8. COMMUNICATION

Recognising our senses

Our sense of touch

Heat receptors on our hands

Reflexes

Signs and communication

Placards

Reporting fires

Phonetic alphabet


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Acids&Bases


9. ENERGY AND HEAT

What is fire

The fire triangle

Starting a fire with the sun

Heating a bimetallic strip

Expanding electric wires

Expansion of solids (ball and ring experiment)

How heat is transferred

Radiation

Radiant heat - the killer in a bush fire

Convection

Conductors

The best conductor of heat

Spontaneous combustion

Absorption and reflection of heat

10. ELECTRICITY

Fuses and circuits

Electrical fire safety

Smoke alarms

Static electricity and lightning

11. WEATHER

Things about weather

Temperature

Humidity

Measuring humidity

Wind

Measuring wind

Rainfall

Assessing fuel moisture content

Weather maps

12. ENVIRONMENT

Ants and fire

Recognising ants

Plants and the Australian Environment

Designing a plant

Fire survival features of plants

Eucalypts , the survivors

Animals and fire

Invertebrates in the bush

Survival of native animals


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Acids&Bases

air& Gases


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Air&Gases


SYLLABUS CORE CONTENT COVERED BY THESE EXERCISES INCLUDE:

4.22.1 (b) Categorise elements as metals and non-metals according to their common characteristics.

4.22.2 (a) Distinguish between elements and compounds.

(b) Recognise that a new compound is formed by rearranging particles rather than creating matter.

(c) Identify when a chemical reaction has taken place.

4.26.1

(b) Identify gases that comprise the greater percentage of the air.

(c) Describe the history and application of the idea of air pressure.

AIR IS A MIXTURE

The following pie graph shows the gases, which are present in air.

Other Gases 0.003%

Nitrogen 78%

Oxygen 20.99%

Argon 0.93%

Carbon Dioxide 0.03%

Use the information in the graph to answer the question below.

From this information, which is the most abundant gas? ...................................................................................................

Which is the gas that supports burning? ............................................................................................................................

Which is the gas that is sometimes used in fire extinguishers? .........................................................................................

What fraction of the air is oxygen? .....................................................................................................................................


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Air&Gases


Experiment HOW MUCH OF TH E AIR IS OXYGEN?

AIM

How much oxygen is used up when something burns?

METHOD

Set up a lighted candle in a rubber stopper and place the stopper into the beaker of water as shown in the

following diagram.

Place a gas jar over the lighted candle so that the gas jar is in the water.

Measure the distance that the water goes up the gas jar.

RESULT

Describe what happened to t he candle and the water:

......................................................................................................................................................................................................

......................................................................................................................................................................................................

Illustrate your answer with a neat well-labelled diagram:


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Air&Gases


CONCLUSION

When something burns it uses oxygen. This oxygen is taken from the ........................................

.

Oxygen takes up about 1/5 of the air. When the oxygen is used up in the gas jar it is replaced by the

water.

Measure the distance between the water and the top of the gas jar

X= ...........................................................................................................................................................................................

Measure the distance that the water goes up the gas jar

Y= ...........................................................................................................................................................................................

Calculate the fraction of the air that is oxygen

X/Y = ..........................................................................................................................................................................................

Account for any differences between your result and the theoretical result for the % of oxygen in the air.

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

HEAT

OXYGEN

FUEL

HEAT

FUEL

In order to have fire the three elements in the

fire triangle must be present.

If one or more of these elements is removed or

not present a fire will not burn.


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Air&Gases


CARBON DIOXIDE AND FIRE

Aim

Is carbon dioxide capable of ext inguishing fire?

Requirements:

vinegar

bicarbonate of soda

gas jar

stopper and candle

large dropper

Method:

Place the candle into the stopper.

Carefully slide the stopper/candle into the gas jar.

Light the candle.

Sprinkle the bicarbonate of soda around the stopper.

Add some vinegar to the bicarbonate of soda.

Result

what I saw: .................................................................................................................................................................................

...........................................................................................................................................................................................

what I heard: ..............................................................................................................................................................................

...........................................................................................................................................................................................

Conclusion.

The gas made in this experiment is called carbon dioxide. It can be distinguished from many other gases because it

extinguishes a flame. The shorthand way of writing carbon dioxide is ............................. The laboratory should have a

carbon dioxide extinguisher located near the exit to the room. Locate this extinguisher and colour in one of the following

diagrams of extinguishers.


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Air&Gases


W HAT SORT O F FIRE EXTINGU ISHER IS TH AT?

Read the following descriptions of some different types of fire extinguishers.

Colour and label the above diagrams accordingly.

TYPE COLOUR USE

WATER ALL RED .............................................................

FOAM ALL BLUE .............................................................

CO2 RED W ITH A BLACK BAND .............................................................

D RY CH EMICAL RED W I T H A W H I TE BAN D .............................................................

W ET CHEMICAL BROW N .............................................................

(check these colors with your local authority as they may change)

The following table lists the different uses of each type of extinguisher:

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................


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Air&Gases


CLASS OFFIRE

TYPE OF FIRE

A B C (E)

Ordinarycombustibles(wood,paper,plastics etc.)

Flammableandcombustibleliquids

Flammablegases

Fireinvolvingenergizedelectricalequipment

Fireinvolvingcooking oilsand fats

INDICATINGCOLOUR

TYPE OFEXTINGUISHER EXTINGUISHER SUITABILITY

WATER

ALCOHOLRESISTANT

FOAM

AFFF TYPEFOAM

CARBONDIOXIDE

(C02)

AB(E)DRY CHEMICAL

POWDER

B(E)DRY CHEMICAL

POWDER

VAPOURIZING

LIQUID(fumes may bedangerous in

confinedspaces)

WETCHEMICAL

YESMost suitable

YES YESMost suitable

NO NO NO

YES

YES

YES YES YES YES NO

NONO NO

NONO NO

NONONONO

NO YES YES YES YES

YES YES NO YES YES

YES YES NO YES NO

YESMost suitable

foralcohol fires

YESMost suitable

except foralcohol fires

F

Choose the best type of extinguisher that might be used in each of the following situations:

A TV set catches on fire .....................................................................................................................................................

A pile of old papers is burning in the corner of a room .......................................................................................................

Some petrol is on the roadway following an accident ........................................................................................................

The oil in the fish and chip shop has ignited ......................................................................................................................

Now answer these questions:

1. Which type of fire extinguisher is found in the laboratory? ....................................................................................................

2. List some other things in the laboratory, which could be used to extinguish a fire?

...........................................................................................................................................................................................

...........................................................................................................................................................................................


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Air&Gases


HOW MAGNESIUM BURNS

Many modern cars have mag wheels to not only make them look good but to

also reduce weight and provide better cooling for the brakes. Motors may

have magnesium bits as well because of its lightness.

BUT! LOOK OUT IF THEY BURN.

THE MAGNESIUM / OXYGEN SNATCH AND GRAB

Magnesium is a metallic element, its chemical symbol is ..........................................................................................................

Oxygen is a non-metallic element, its chemical symbol is .........................................................................................................

AIM

Can magnesium combine with oxygen to form a new

substance?

METHOD

Hold the magnesium ribbon with metal tongs and place the

magnesium into the Bunsen flame.

DO NOT STARE AT THE FLAMING MAGNESIUM -

look at it out of the corner of your eye.

Make sure you have a heat proof mat and wear safety goggles.

RESULT

Describe the flame and how the magnesium burnt ....................................................................................................................

...........................................................................................................................................................................................

What was left after the magnesium burnt? ................................................................................................................................

...........................................................................................................................................................................................

What was the main energy type produced in this reaction? ......................................................................................................

...........................................................................................................................................................................................


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Air&Gases


CONCLUSION

When things burn they combine with oxygen in the air. Oxygen is part of the FIRE TRIANGLE .

MAGNESIUM + OXYGEN MAGNESIUM OXIDE

(element) (element ) (compound)

Do you think that burning magnesium would be easy to put out?

.............................................. currently available extinguishers are very suitable for putting out this type of fire. Rural fire

fighters would probably respond to this type of fire by covering with soil and containing the fire.

Suggest a reason why this method of extinguishment could be successful. .............................................................................

...........................................................................................................................................................................................

Do you think that all of the ash, smoke, and dust formed in this reaction would be heavier or lighter than the original strip of

magnesium metal? ................................ How come? ................................................................................................................

...........................................................................................................................................................................................

FACT OR FICT IO N ? In the olden days before many rural communities had electr icity, travelling picture shows

travelled around the bush. They used sticks of magnesium to provide the light for the projectors. This used to work OK

but there was the added danger of .................................... !FIRE!!!

See if you can find out some more about this.

HEAT

OXYGEN

FUEL


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Air&Gases


WATER AND HYDROGEN

Our society today loves to live in, around, above and below water. We use it to drink, to clean, to cool, to wash, to get rid of

wastes and to play with. In fact our life would be pretty dull without water. Some people even think that we might be able to

use water as an energy source. What do you think?

The chemical formula for water is ..................... This means that in one m................... of water there are two a ................of

h.................................. and one a.........................of o............................

W ater can be made by burning hydrogen with oxygen. W hen this happens there is a very loud explosion.

The percentage of oxygen in air is 21%. Hydrogen PO PS when ignited in air.

W hen hydrogen is ignited in pure oxygen... W ELL!!!!!

ASK YOUR TEACHER TO DO T HIS AS A D EMONSTRATIO N

DO NOT DO IT YOU RSELF.

HCl

Mg

H2 Generator O2 Generaror

H2 O2

Mn O2

H2 O + detergent


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Air&Gases


When the bubbles containing the mixture of hydrogen and oxygen are ignited it gives off a fair bit of energy doesnt it. If we

could utilize this energy change we could possibly power our vehicles using hydrogen.

HYDROGEN + OXYGEN WATER

(element) (element) (compound)

BUT... from where can we easily get the hydrogen and oxygen to make all this happen?

Observe the teacher demonstration showing how electricity can be used to change water into hydrogen and oxygen .

Which tube do you think contains the hydrogen and which tube do you think contains the oxygen?

Label these gases on the diagram.

WATER HYD ROGEN + OXYGEN

SO!!!! We can start with water to make hydrogen and oxygen and use these as fuels and end up with water again.

SOURCE OF WATER = TH E OCEAN

SOURCE OF ELECTRICIT Y = SOLAR

POLLUT ION = ZERO (or does it)

+ to a power source-


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Air&Gases


Form small groups and discuss this and /or research this form of energy usage.

Share your findings and ideas with the rest of the class. Write your findings here. ...................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

Did you know?

ROCKETS TAKE TH EIR OWN OXYGEN SUPPLY W ITH TH EM.

The fuels they burn, burn with pure oxygen.

This really gives them some get up and go.

Cars do not function as well at higher altitudes. Why would this be so? ...................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................


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Air&Gases


THE BIGGEST STRAW IN THE WORLD

AIM

W hat is the furthest distance that water can be sucked up a straw?

METHOD

obtain a clean long straw

(a long length of rubber tubing would be ideal).

container of water from which you are going to suck out the water.

Suck the water into the straw from different heights.

Record all observations.

RESULT

CONCLUSION

The highest distance that I could suck up the water was ...........................................................................................................

In theory we should be able to raise the water by sucking to a height of 10 metres.

This theoretical value is nearly impossible to achieve however.

Suggest some reasons as to why you think this might be the case. ..........................................................................................

...........................................................................................................................................................................................

Firefighting pumps should always be placed as close to the water source as possible. Seven metres is probably a practical

distance to which water can be raised.


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Air&Gases


AIR HAS WEIGHT AND CAN EXERT PRESSURE

AIM

Can a balloon be made to inflate itself inside of a flask?

METHOD

1. Heat water in f lask until it is boiling.

2. Remove from heat and carefully place a balloon over the top of the flask. DONT BURN YOURSELF.

3. Allow the flask to cool.

RESULT

Draw and describe what happened to the balloon.

.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................

.................................................................................


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Air&Gases


.................................................................................

CONCLUSION

Heating the water causes it to ........................................ and change to ........................................... The steam fills the flask.

When the balloon is placed over the neck of the flask it prevents outside air getting back in. As the steam cools it

................................... to form water, leaving an empty space or ................................... inside of the flask. Air tries to get in,

so it pushes against the balloon and causes it to inflate inside of the flask.

TEACHER DEMONSTRATIONS

TH IS ACTUALLY HAPPENED

The contents of a feed silo on a large dairy farm caught on fire. The farmer was instr ucted to seal up the silo so as to

star ve it of oxygen and therefore extinguish the fire. The available oxygen was used up by the smouldering feed and

this resulted in the formation of a partial vacuum in the silo. Air pressure caused the sides of the silo to crumple

thereby breaking the seal. Fresh air rushed in and fed the fire. A type of back draft resulted. The fine particles of feed

in the silo exploded and the top of the silo was blown 50 metres away from the rest of the silo.

Cool

1. 2.

Demonstration 1 Demonstration 2

Observations ..............................................................................................................................................................................

...........................................................................................................................................................................................

Explanation ................................................................................................................................................................................

...........................................................................................................................................................................................


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Air&Gases


matter


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Matter


SYLLABUS CORE CONTENT INCLUDED IN THESE EXERCISES ARE:

4.14 (a) Define all matter as being made up of particles that are continuously moving and interacting

(b) Describe expansion and contraction of materials in terms of simple particle motion

4.12 (a) Apply the term solid, liquid and gas to a range of everyday substances

(b) Identify when a physical change occurs by observing evaporation, condensation, boiling, melting and freezing

4.22.2 (a) Distinguish between elements and compounds

4.26.2 (a) Recognise the importance of water.....

THE BIG FREEZE

Your teacher will have a carbon dioxide fire extinguisher at the front of the laboratory. When the extinguisher is shaken do

you hear things that : -grind together or lap about or woof around

In a textbook read about the properties of solids, liquids and gases.

Do you think that the carbon dioxide in the extinguisher is a

solid? or liquid? or gas?

......................................... Why? ...........................................................................................................................................

....................................................................................................................................................................................................

When the carbon dioxide is released from the extinguisher it WOOFS out as a gas. If the extinguisher is discharged for a

while you will notice ice around the end of the outlet.

CO2 MAKES A LOU D ROARING N OISE AN D IS

INTENSELY COLD W HEN DISCHARGED

List some precautions that should be used when a CO2 extinguisher is discharged:

...........................................................................................................................................................................................

...........................................................................................................................................................................................

HEAT ENERGY IS N EEDED TO CH AN GE AN OBJECTS STATE FROM A SOLID TO A LIQU ID TO A GAS.

HEAT ENERGY MAY CO ME FROM TH E AIR, OR OTHER OBJECTS. HEAT ENERGY IS TAKEN IN AND CAN

MAKE THE SURROU NDS FEEL COLD. A S MATTER CHAN GES BACK TOW ARDS SOLID,

HEAT ENERGY IS GIVEN O UT.

In the following boxes draw how you think the particles inside of the CO 2 extinguisher may be organised and how the

particles would be organised as they leave the extinguisher.

Inside the extinguisher Outside the extinguisher

CO2 is contained at a high pressure in its cylinder.

W hen the cylinder is discharged the pressure is released and the CO2 vaporises.


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Matter


THE PRESSURE IS OFF

AIM

W ill a release in pressure cause a liquid to boil?

METHOD

Place a beaker of water into a bell jar attached to a vacuum pump. Start the pump and reduce the pressure in the jar.

Observe the jar and the beaker for signs of boiling or evaporation.

RESULT

1. Describe the appearance of the water in the beaker. ............................................................................................................

...........................................................................................................................................................................................

2. Describe any appearance of steam or evaporation. ..............................................................................................................

...........................................................................................................................................................................................

CONCLUSION

1. Would you say that the water boiled? ....................... Why? ..................................................................................................

...........................................................................................................................................................................................

2. Would you be prepared to put your hand in the water? .........................................................................................................

Why? ..........................................................................................................................................................................................

3. Circle the following statement which you believe to be true.

Boiling depends upon temperature.

Boiling depends upon pressure.

Boiling depends upon heat and pressure.

Bell Jar

Beaker

Water

Vacuum Pump


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Matter


COOLING OFF

AIM

W hy is it import ant to allow free evaporation of sweat from the body if we want to keep cool?

METHOD

1. Place a drop of alcohol onto the most heat sensitive part of your arm, wait and observe.

2. Place some wet cotton wool onto the end of a thermometer and measure the temperature over a 2 minute period.

3. Place the same amount of wet cotton wool onto a thermometer again, but this time blow onto the cotton wool and

record any temperature changes over the 2-minute period.

RESULT

1 When I placed the alcohol onto my arm and left it there it ......................................................................................................

...........................................................................................................................................................................................

2 time temperature

start

...........................................................................................................................................................................................

30 sec.

...........................................................................................................................................................................................

60 sec.

...........................................................................................................................................................................................

90 sec.

...........................................................................................................................................................................................

120 sec.

...........................................................................................................................................................................................

3 time temperature

start

...........................................................................................................................................................................................

30 sec.

...........................................................................................................................................................................................

60 sec.

...........................................................................................................................................................................................

90 sec.

...........................................................................................................................................................................................

120 sec.

CONCLUSION

1. Did the alcohol evaporate?...................... This evaporation makes your arm feel.......................... Evaporation takes heat

away from your arm.

2. Blowing onto the wet cotton wool increases the rate of evaporation. Did this increased rate of evaporation cause greater

cooling?.............................................


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Matter


KEEPING COO L

Use the following words to complete the passage below:

evaporating

circulation

open

hot

cool

rate

cooling

sweat

Sweat ................................................... from our bodies causes our bodies to cool down. Anything which hampers this

........................................................of evaporation will affect our bodys ........................................system. When working in

very .....................................conditions such as experienced by fire fighters we should dress in such a way so as to obstruct

as little as possible the escape of heat from the body by the evaporation of ............................. . Firefighters should have

trouser legs and shirt or overall sleeves ............................................at the cuffs, and shirt and overall necks left free to

permit maximum ..........................................................................of air and allow evaporation of sweat from the body to

................................................. the body down.


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Matter


WATER

Water occupies over three-quarters of the earths surface. Water is the major component of all living things. The water in a

plants body is absorbed through its roots. Animals obtain their water by drinking or by eating plants and other animals. We

can survive for a short time without food but we cannot survive very long without water. The moisture content of plants is a

major determining factor in bush fire behaviour.

WATER IN LIVING TH INGS

AIM

How much water is in the body of a plant?

METHOD

1. Determine the mass of a handful of fresh green grass clippings.

2. Place the clippings into a clean dry beaker and place into a drying oven until the grass is completely dried out.

3. Determine the mass of the dried clippings.

4. Calculate the mass of water in the green plants.

5. If time permits, repeat steps 1-4 for some other local plants. (Discuss the variables with your teacher first).

RESULT

(1) MASS OF FRESH CLIPPINGS ............................. g

(2) MASS OF DRY CLIPPINGS ........ .. .. ... .. .. ... .. .. .. .g

DIFFERENCE (1) - (2) = ............................. g OF WATER


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Matter


In ............................. grams of fresh grass there are ............................. grams of water.

mass of water X 100 = % of water

mass of fresh grass

X 100 = ................. % of water

CONCLUSION

1. The percentage of water in the green living grass is ............................. %. How does this compare to the percentage of

water in other living things? ................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

2. List some factors, which might alter the amount of moisture in grasses and other plants: ....................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

The amount of moisture in grasses and other vegetation is a determining factor in bush fire behaviour. The rate at

which a fire will spread increases dramatically when the fuel moisture content falls below 6-8%. This increase is due to:

Increased ease of ignition

More effective radiation

Great ly increased combustion rates


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Matter


LEAF BURNS ONLY IF STRAIGHT DOWN (OR NOT AT ALL)All fuels too wet if this leaf in area to be burnt. O.K. if only in WET TYPES not to be burnt.

LEAF BURNS IF ANGLED DOWNWARDS BUT NOT IF LEVELFine fuels in this leafs position will only burn if on slope or in wind.O.K. if the leaf from BOTTOM of litter in burn area, or from WET TYPES not to be burnt.

LEAF BURNS IF LEVEL BUT NOT ANGLED UPWARDS Fine fuels in this leafs positionwill burn but very slowly unless helped by wind, slope and fuel continuity. If on top of litterlayer, wait another day.

LEAF CAN BE ANGLED UPWARDS AND STILL BURNFine fuels in the same positions as this leaf are dry enough to burn.O.K. if this leaf is from TOP of litter. RISKY if from BOTTOM.

LEAF BURNS IF HELD STRAIGHT UP All fine fuels very dry and flammable.Fire will run up stringy bark trees. Embers and burning material will escape, especially ifwindy. DONT BURN

wet

moist

borderline

dry

too dry

IS IT SAFE TO BURN?

AIM

Can I accurately predict whether or not it is safe or practical to undertake a burn to reduce the amount of fuel?

( This is known as hazard reduction burning)

METHOD

Choose several dead leaves from a variety of trees in your vicinity.

Sheltered from any wind, light the end of the dead leaf and once lit take the ignition source away. (Ideally this should be

done in the laboratory under controlled conditions and must be done with supervision by your teacher)

Record the way in which your leaves burn according to the information in the following table.


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Matter


RESULT

Type of leaf locality how it burns

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

CONCLUSION

Indicate, giving reasons, whether you think it would be suitable to undertake a hazard reduction burn today. .........................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

Fuel reduction burning is usually carried out when the upper litter is dry and the litter next to the soil is moist.

In these conditions fires burn quietly during daylight but go out at night.

INSTANT LY VAPORISIN G W ATER

W hen a fire occurs in a flammable or combustible liquid some heating of the liquid takes place. If the liquid becomes

heated to above 100 degrees Celsius any water entering the liquid may vaporise. W hen water vaporises it expands

1700 times. This sudden expansion may cause quantities of the burning liquid to be ejected out of the container.

NEVER PUT WATER ON TO BURNIN G LIQUI D FIRES

How much water would be in one cup of water? ............................................................................................................... ml

How much space would this cup of water occupy if it were to expand 1700 times?.......................................................... L


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Matter


BURSTING OF CYLINDERS

Any sealed container is likely to burst when exposed to fire. Pressure release devices on some types of gas cylinders may

relieve internal pressure, but the cylinder may still fail if the fires heat is sufficient to weaken the cylinders metal shell.

Examine the gas storage facility or gas bott le at your school and see if you can recognise a pressure relief device.

When a cylinder fails a substantial amount of the liquid inside of the cylinder will immediately vaporise and expand.. When

this occurs with a flammable gas, a large fireball will be formed, in some cases it could injure people 500 metres away.

Name different objects, which would be 500 metres away from the schools gas cylinder

1. ............................................................................... 6. ...............................................................................

2. ............................................................................... 7. ...............................................................................

3. ............................................................................... 8. ...............................................................................

4. ............................................................................... 9. ...............................................................................

5. ............................................................................... 10. ...............................................................................

The remnants of the cylinder may rocket over several hundred metres, trailing burning contents as they go. This phenom-

enon is called a boiling liquid expanding vapour explosion, or BLEVE.

Is there any likelihood of a BLEVE happening in your town? ....................................................................................................

...........................................................................................................................................................................................

In groups decide upon a list of planning proposals that would reduce the chances of a BLEVE occurring?

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Matter


WALKING ON WATER

AIM

How do water striders and other water walkers get across the surface of water and will this be affected by the

addition of detergent?

METHOD

Fill a beaker with water and carefully place a pin onto the surface.

Add extra pins.

Add a few drops of detergent to the water.

RESULT

1. Describe what you did to get the pins to float. .......................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

2. What happened when you added extra pins? ........................................................................................................................

...........................................................................................................................................................................................

3. ZOOM onto the pin on the surface of the water. DRAW how the pin sits on the surface of the water. Place labels on your

diagram to show what you see.

4. What affect did adding detergent have? ................................................................................................................................

...........................................................................................................................................................................................

CONCLUSION

1. What seems to be on the surface of the water? ....................................................................................................................

2. When detergent is added what do you think happens on the surface of the water? .............................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................


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Matter


Use the following words to complete the passage below: (words may be used more than once)

detergents

wetting

chemicals

larger

cling

droplets

skin

tension

particles

water

surface

The .............................................. which appears to be on the surface of water is caused by WATER TENSION. This causes

the particles of water to .............................................onto each other and can stop the water from mixing with other particles.

Water .............................................. form due to .............................................. tension. .............................................. have

the affect of disturbing water ..............................................and the skin of water would tend to disappear.

Firefighting vehicles use ........................................... agents in the water. Wetting agents are ..................................................

which, when added to water, break the surface ..............................................causing the .............................................. to

spread out and so cover a .............................................. area.


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Matter


FORMING COMPOUNDS

AIM

Can I determine how much oxygen combines with magnesium to form a new compound?

METHOD

Clean a piece of magnesium ribbon (try dipping it into some dilute hydrochloric acid).

Accurately measure the mass of the magnesium using a triple beam balance. Describe how you are going to do this. ......

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

Check your measurement with that obtained on an electronic balance.

Similarly obtain the mass of a clean dry crucible.

Heat the magnesium in the crucible with the lid on.

Periodically lift the lid.

Continue to do this until all of the magnesium has reacted.

When cool measure the mass of the products of the reaction.

Write your observations in the space provided and complete the taste.

RESULT

Observations: .............................................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

Crucible Lid

Crucible

Tripod

Mg

Crucible Tongs

Bunsen Burner


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CONCLUSION

Why did you periodically lift the lid of the crucible? ............................................................................................................

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What element does the magnesium combine with to form the ash? ..................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

In this experiment I found that .............................. grams of magnesium reacted with .............................. grams of ........

.............................. to form .............................. grams of ....................................................................

MAGNESIUM + .................................................. MAGNESIUM OXIDE

Extension Work

Given that the valency of magnesium is +2 and the valency of oxygen is -2, write the formula for magnesium oxide.

.................................................................................................

Now write a balanced equation for t he complete reaction.


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Matter


BURNING SUGAR

AIM

W hich elements combine together to form sugar?

METHOD

Place a spoonful of sugar into a test tube.

Use a Bunsen burner to heat the test tube containing the sugar.

Hold a second test tube containing ice above the first.

Draw a labelled diagram of your experiment.

RESULT

Observation

Change in colour of sugar ..........................................................................................................................................................

Smell ..........................................................................................................................................................................................

What formed on the cold test tube ............................................................................................................................................

CONCLUSION

The product, which formed on the cold test tube, was ..............................................................................................................

The chemical formula for this substance is ...............................................................................................................................

The product left in the test tube was like ...................................................... .The chemical symbol for this is ........................


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Matter


When you heated the sugar you decomposed it into simpler substances. The elements present in these simpler substances

are .............................................................................................................. and .....................................................................

The chemical formula for sugar is C12H22O11.This means that it is made up ................... atoms of C...............................,

........................................ atoms of H................................. and ........................................atoms of O....................................

Naturally occurring substances normally burn to form CO2 and H2O.

In a bush fire the smoke is a mixture of this and carbon.

Fire is a chemical reaction which reduces complex organic molecules into simpler inorganic molecules

Do you know the difference between the terms ORGANIC and INORGANIC?

ORGANIC = ...............................................................................................................................................................................

...........................................................................................................................................................................................

INORGANIC = ............................................................................................................................................................................

...........................................................................................................................................................................................

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Do you know the difference in the terms complete and incomplete combustion?

Complete Combustion = ............................................................................................................................................................

...........................................................................................................................................................................................

Incomplete Combustion = ..........................................................................................................................................................

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MaterialScience

dk/ FireScience NSW Rural Fire Service

materialscience


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MaterialScience

SYLLABUS CORE CONTENT COVERED BY THESE EXERCISES INCLUDE:

4.28.2.1 (b) List substances that act as fuels, the conditions under which they burn and relate these to everyday

situations

(c) Identify fossil fuels and describe some of their uses

5.24.2 c) Carry out chemical reactions between different elements and between elements and compounds including:

(i) Reactions involving oxygen, including combustion and corrosion

(d) Classify compounds as organic or inorganic based on common characteristics including the presence or

absence of carbon

(e) Give common examples of organic and inorganic compounds and where they occur

W HAT CARS ARE MADE OF

In the following diagram of a bush fire vehicle, identify the materials, which are used in its manufacture.

List them in the table, which follows. eg.

name of part what it is made of name of part what it is made of

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eg. tyre rubber


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MaterialScience


Use the table below to answer the questions about the physical properties of metals.

metal symbol cost $/kg density strength

aluminium Al 2 2.7 80

copper Cu 4 8.9 150

iron Fe 0.02 7.9 120

tin Sn 8 7.3 30

zinc Zn 2 7.1 150

1. Which is more dense, iron or aluminium? ..........................................................................................................................

2. From the table construct a profile comparing iron and aluminium.

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3 Aluminium is now used in the manufacture of water tanks on bush fire vehicles. List some reasons why you think that

aluminium is used for this purpose and why some other metals arent quite as suitable. ..................................................

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4. What disadvantages might be involved in using aluminium to build these water tanks? ...................................................

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5. Using a current newspaper, find the current cost (in Australian dollars/kg) of the metals in the above table. Put your .....

findings in the table below.

CURRENT PRICES OF METALS (__/__/__)

METAL COST (Australian $/kg)

Aluminium ...........................................................................................................................................................................

Copper ................................................................................................................................................................................

Iron .....................................................................................................................................................................................

Tin.......................................................................................................................................................................................

Zinc .....................................................................................................................................................................................


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MaterialScience

W HAT METAL IS BURNING?

AIM

What causes the different coloured flames to appear when we burn different objects?

METHOD

Obtain samples of various metallic salts.

Place some hydrochloric acid and zinc into a clean evaporating basin.

As it effervesces hold the Bunsen flame above the bubbles.

Sprinkle a small sample of one of the metallic salts (e.g. CuSO4) onto the bubbles and once again hold the flame above.

Clean out the evaporating basin and repeat the procedure with different metallic salts.

Alternatively, your teacher may have prepared spray bottles containing solutions of metallic salts which can be

sprayed directly into the blue flame of the Bunsen burner.

Record your results in the table below.

RESULTS

METALLIC SALT TESTED COLOUR OF FLAME

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MaterialScience


CONCLUSION

1. Different metals burn with their own characteristic flame colour. Suggest some practical implications of this ...................

procedure. ..........................................................................................................................................................................

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2. Explain how this could help police to solve crimes. ............................................................................................................

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3. When glossy magazines burn they often emit spectacular, coloured flames. Why? ..........................................................

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...........................................................................................................................................................................................

4. Use the library or your textbook to research the characteristic flame colours of the various metals (e.g. calcium, ...........

strontium, sodium) and record your findings in the table below.

METAL FLAME COLOUR

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How does your research compare with the results of the experiment? .....................................................................................

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During structural fires there are many different coloured flames.

This indicates to the firefighters that some metals or metallic ions may be involved in the fire.

Some of these metallic ions may be constituents of some nasty chemicals so the firefighter should beware.


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MaterialScience

RUST

Rusting is a chemical reaction between the elements iron and oxygen.

Iron can also be made to combine with oxygen by burning.

Another name for this process is oxidation.

IRON + OXYGEN IRON OXIDE

Documents

Fire Science Workbook 1